Magnetoresistive effect elements such as a giant magnetoresistive effect (GMR) element and a tunnel magnetoresistive effect (TMR) element having a configuration in which a reference layer as a magnetization fixed layer, a nonmagnetic spacer layer, and a magnetization free layer are stacked in this order are known. Among the magnetoresistive effect elements, the TMR element that uses an insulation layer (tunnel barrier layer) as the non-magnetic spacer layer generally has high element resistance but can realize a high magnetoresistive (MR) ratio, compared to the GMR element that uses a conductive layer as the non-magnetic spacer layer. Thus, the EVER element has drawn attention as an element used in a magnetic sensor, a magnetic head, a magnetoresistive random access memory (MRAM), and the like (for example, Patent Literatures 1 and 2 below).
A technology called “spin injection magnetization reversal” in which a spin transfer torque (STT) is applied to the magnetization free layer from electron spins by causing a spin-polarized current to flow through the magnetization free layer is known as a method of reversing the magnetization direction of the magnetization free layer of the TMR element. For example, applying this technology to the MRAM can reduce the size of a memory cell and thus can achieve high density for the reason that an interconnect for magnetic field generation for reversing the magnetization direction of the magnetization free layer is not necessary. Generally, the MRAM that uses the magnetization reversal technology based on the STT is called an “STT-MRAM”.
A manufacturing process for a semiconductor device called the STT-MRAM may include an annealing step under a high temperature atmosphere of, for example, 300 degrees Celsius or higher (for example, Patent Literatures 4 to 6 below). The annealing step under the high temperature atmosphere is performed in order to improve the film quality and the crystallinity of the TMR element included in the STT-MRAM.